Device and method for the active monitoring of the safety perimenter of a motor vehicle

ABSTRACT

The invention relates to a device for the active monitoring of the safety perimeter of a motor vehicle, which is used to detect moving objects or static obstacles inside said safety perimeter. The inventive device includes a first sensor which covers a first detection zone comprising at least part of a blind angle of the vehicle and which sends input signals to an information-processing device which generates output signals for means used to alert the driver. Moreover, the device also includes at least one second sensor which covers a second detection zone and which forms one unit with the aforementioned first sensor. According to the invention, the first and second sensors co-operate in order to cover a combined detection zone containing the blind angle, which is increased in relation to the zone covered by the first sensor and which forms a section of the safety perimeter. The above-mentioned unit comprising the first and at least one second sensor use the same alarm means.

FIELD OF THE INVENTION

The invention refers to an active monitoring device suitable for thedetection of moving objects or static obstacles within a safetyperimeter of a motor vehicles whether this is in motion or not, withsaid device comprising one or more assemblies of at least two detectors,where in general, a first detector has a first detection angle and afirst radius of action and a second detector has a second detectionangle and a second radius of action, with said detectors transmittinginput signals to at least one data processing device that generatesoutput signals capable of activating some warning means the driver abouta risk situation within a determined, clearly identified area or zone insaid safety perimeter. It is intended that the device can alsooptionally provide additional information in the form of imagesdisplayed on a screen.

The invention also concerns an active monitoring method within a safetyperimeter of a motor vehicle.

State of the Technique

Safety devices of the type described at the beginning are well-known.They are usually employed to cover the blind angle in a side lane of amotor vehicle and to provide the driver with an alarm signal in the caseof a dangerous situation.

A device of this type is described in document EP-A-591743.

Document WO01/61371 A2, from the same applicant, described some devicesfor the detection of objects, of the type that are mounted on motorvehicles and which are suitable for detecting an object situated in theblind angle. These devices comprise a detector with a receiver that candetect electromagnetic waves, with a focalising device and aphotosensitive device that transforms the electromagnetic waves intoelectrical signals. An electronic circuit transforms the electricalsignals into digital signals that are analysed by a logic circuit inorder to analyse the presence of objects within the blind angle with amovement relative to the vehicle. The logic circuit emits variableoutput signals in function of the analysis results. The detection deviceincludes indicating elements that are perceived by the driver. Ingeneral, two of said detection devices are included in the same vehicle,one on each side of the vehicle, for example, in each of the outsiderear-view mirrors. In these cases, the two detection devices aresubstantially identical, with each one having the function of coveringone side zone of the vehicle.

Frequently, these detection devices do not only cover the blind angle,but also a zone that is visible via the corresponding outside rear-viewmirror. This is a positive feature because they perform a redundantmonitoring function with respect to the non-permanent visual monitoringcarried out by the driver, which in turn increases safety.

Patent EP-A-443185 describes a procedure and a device for assisting amotor vehicle driver during a lane change, which is based on themeasurement of relevant data with respect to the traffic behind saidvehicle and specifically in carrying out various successive measurementsof distance with respect to other vehicles, determining the differencein accelerations between both vehicles in order to maintain a minimumsafety distance, and using these data to produce assessment indices thatare visually or acoustically indicated to the driver. In the productionexample shown in reference to FIG. 2 of the drawings, it shows the useof three distance measuring heads installed in the vehicle's rear-viewmirrors and in the upper, central and rear sections of the vehicle,respectively, covering two lanes on the sides and one central behind thevehicle, controlling the signals coming from said measurement headsusing time multiplexing.

Document EP-A-454516 describes a device for the display of obstacles inthe vehicle's path, which makes use of two video cameras with CCD imagesensors that are differentiated in function of the spectral field towhich they are sensitive and with some means of differentiallyprocessing the two acquired video images in order to form a third imageof the field open to the vehicle, containing only an image with enhancedcontrast of the vehicle.

Document U.S. Pat. No. 5,424,952 describes the use of some detectionmeans, including two optical systems, for the detection of objectssituated in an area adjacent to a vehicle from two different points andin order to form images of said objects that are displayed on a screen.In the explained production, two image detectors are described, whichinclude a pair of horizontally spaced optical systems operating jointlyto form two images on which to use trigonometric principles to detectthe distance to each object by deviation between the cited images.

Document U.S. Pat. No. 5,699,057 describes a warning system comprising apair of stereoscopic cameras and some means of image recognition fortheir processing and the issuing of a warning signal to the user by somemeans of recognition of images of possible objects situated in an areaadjacent to the vehicle.

However, none of said background documents describes the layout of twoor more detectors in particular, cooperating together to cover, in acomplementary fashion, two or more contiguous zones or with partialoverlap, but that jointly cover a determined detection zone of aprefixed, blind angle, within a safety perimeter, enlarging theeffective detection zone of said blind angle accessible to a singledetector and where the two or more detectors take part equally in thegeneration of alarm signals for predetermined situations of the presenceof objects in the specific covered monitored field.

Moreover, the detection devices in the current state of the techniqueusually have a quite limited radius of action, which reduces theireffectiveness, particularly in the case of very long vehicles.

This document employs the expression “motor vehicle” to describe anytype of vehicle, whether this is a saloon car, a bus, a lorry(articulated or not) and any type of special transport etc, includingany of the previous type with a trailer.

A blind angle, according to the terminology employed in this invention,is a n area of vision, adjacent to the motor vehicle, which cannot bedirectly seen by the driver under normal driving conditions. Therear-view mirrors, especially the outside ones, are intended to minimisethese areas on the sides of the vehicles. The state of the techniquerecognises the use, particularly in very wide and/or long vehicles, of alarger number of mirrors, or mirrors with greater angles of curvature,in order to reduce the blind angles, as found in various directives.However, under normal driving conditions, the driver cannot besimultaneously watching or attending to several mirrors, which makes adevice, such as the one proposed in this invention, an additional meansof assistance that can prevent any manoeuvre, especially lane-changing,in a situation where there is another nearby vehicle with the potentialrisk of collision within what this invention defines as a safetyperimeter.

A BRIEF DESCRIPTION OF THE INVENTION

According to the invention, it is proposed to cover said safetyperimeter, by means of one or more detector assemblies, each one fittedwith at least two detectors, applied to the coverage of, for example,each of the sides, together with the front and the rear of the vehicle.In general, each assembly comprises two detectors: a first detector witha first angle of detection and a first radius of action covering a firstzone of detection t hat includes a t I east part of a blind angle ofsaid vehicle, together with a second detector, with a second angle ofdetection and a second radius of action covering a second zone ofdetection, cooperating said first and at least a second detector toprovide cover of a joint detection zone of said blind angle, which isenlarged with respect to that covered only by said first detector andwhich constitutes a sector of said safety perimeter. Said first andsecond detectors transmit input signals to at least one data processingdevice that generates output signals that are capable of activating themeans to warn the driver of a dangerous situation in one of themonitored sectors and of optionally providing additional information inthe form of images displayed on a screen.

The employed detectors are usually different and in particular, thefirst detection angle is larger than the second detection angle, withthe first detector covering at least part of a blind angle of the motorvehicle and the second radius of action is greater than the first radiusof action.

By having two different detectors of the cited type available, itbecomes possible to combine two characteristics that would otherwise beincompatible: the detection angle and the radius of action. On the onehand, it is necessary to have the largest possible detection angle inorder to better cover the blind angle. However, on the other hand, it isrequired to have the largest possible radius of action in order to beable to detect an approaching vehicle at a greater distance so that thecorresponding alarm signal is issued while the driver still hassufficient time in which to react. However, if a detector's radius ofaction is to be increased it then becomes necessary to add a telephotolens, which will reduce the detection angle. In this active monitoringdevice, in accordance with this invention, in a production example,there is a detector, the first detector, which has a wide detectionangle and therefore satisfactorily covers the blind angle, while theother detector is given a large radius of action, for example, by addinga telephoto lens, or by locating it at a certain distance behind thefirst, which will enable the detection of approaching vehicles at asufficiently large distance. In this way, the two detectors worktogether and the active monitoring device as a whole, complies with thetwo characteristics: that of large detection angle and radius of action.Preferable, the first and second detectors cover zones that partiallyoverlap so that the detection and tracking of an approaching vehicle maybe carried out in the joint detection zone without any solution ofcontinuity. In this sense, it is also advantageous that both the firstand second detectors are on the same side or in the same zone (front orrear) of the motor vehicle.

The invention also has the purpose of being an active monitoring deviceof the type described at the beginning and characterised in that thefirst and second detectors are oriented towards the same side laneadjacent to the motor vehicle and where the second detector is suitablefor detecting a motor vehicle in the side lane at a distance from theactive monitoring device carrying vehicle that is greater than the firstdetector.

In fact, in this way, it is also possible to make the requirements ofwide detection angle and radius of action compatible. It is possible forthe two detectors to be physically together or very close (for example,both housed in a body or support on the same outside rear-view mirror),but possessing different characteristics (detection angle and radius ofaction), or it is possible for them to have the same characteristics,but installed in different locations on the motor vehicle, which wouldenhance the overall characteristics of the active monitoring device.Therefore, for example, in the case of long motor vehicles, or thosewith trailers, the active monitoring device as a whole will have itsradius of action notably enhanced by installing a second detector at therear of the vehicle, even in the case of the second detector having thesame characteristics as the first detector. Logically, it is alsopossible to combine both effects (a different location on the motorvehicle, together with different characteristics) in order to obtain anactive monitoring device with a large radius of action and a widedetection angle.

In general, the data processing device of said at least two detectorsoperates by simultaneous, but separate processing of each of the inputssignals coming from the detectors, and the same said two detectors sharethe same warning means, for example, one or more warning lights or anacoustic alarm.

Another purpose of the invention is an active monitoring method that isapplicable to any motor vehicle, in particular, saloon cars, lorries,buses, articulated vehicles (such as, for example, lorries consisting ofa tractor and a trailer), and special transport, together with any ofthe previous ones that also include a trailer. In the latter case, itmust be understood that the second and/or a possible fourth detector(which is described later) may be installed on any part of the vehicle(the front part or the trailer). In a more general sense, it may beconsidered that a motor vehicle, as this expression has been employed inthis document, includes any assembly of elements that are pulledtogether along a street or highway.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and characteristics of the invention can be appreciatedfrom the following description in which, without having any limitingcharacter, describes certain preferential construction modes of theinvention, with reference to the accompanying drawings. The figuresshow:

FIG. 1 is a schematic plan view of a saloon car indicating a series ofareas existing within a safety perimeter surrounding said automobile.

FIG. 2 is a schematic view of a saloon car with an active monitoringdevice in accordance with the invention, showing the zones of vision viathe rear-view mirrors and of detection that are covered by cariouscooperating detectors.

FIG. 3 is a schematic view of a bus with an active monitoring device inaccordance with the invention.

FIG. 4 is a logic diagram of one possible treatment method for theoutput signals from each detector after processing.

FIG. 5 is a schematic view of an automobile with another activemonitoring device in accordance with a variant of execution of theinvention.

FIG. 6 is a schematic view of a coach or lorry with an active monitoringdevice intended to cover a front blind angle, which is implemented inaccordance with the invention's principles.

DETAILED DESCRIPTION OF SOME FORMS OF CONSTRUCTION THE INVENTION

Preferably, the active monitoring device detectors will capture imageswhich, in most cases, are processed separately and simultaneously. Theprocessing operation is advantageously carried out by a data processingdevice adjacent to each detector and said data processing devicegenerates output signals that are sent to an interface inside thevehicle, which receives the output signals from the various dataprocessing devices and activates the warning devices and optionally,information devices. It is also possible to transmit all or part of thecaptured image inside the car so that it can be viewed directly by thedriver, however, it is preferred that only said output signals are sentas visual or acoustic warnings, since this will simplify the activemonitoring device, make it more economic, faster and provide the driverwith an immediately intelligible signal, even in poor visibilityconditions (darkness, rain, fog and dazzling situations etc), withoutinterfering with said driver's attention.

Preferably, the first detector is built into the body or supportstructure of an outside rear-view mirror on the motor vehicle. In thisposition, it can provide optimum coverage of the blind angle.Advantageously, the second detector is installed at the rear or one sideof the motor vehicle, more rear than the first detector. In this way,the second detector, which is intended to mainly detect objects at agreater distance, will gain a distance equivalent to the length of themotor vehicle with respect to the first detector. This is particularlyimportant in the case of long motor vehicles, such as buses and lorries,with or without trailers (for example, twenty metres) since this means asignificant part of the radius of action of the first detector, whichcould be, for example, thirty metres. In such cases, it may beadvantageous that the second detector is not installed at the rear ofthe vehicle, but instead, at an intermediate point of the same. Theinvention also contemplates the use of three or more detectorscooperating together to cover a given area of the safety perimeter and,in general, a blind angle and an extension of the detected zone of saidblind angle.

Usually, the first and second detectors are installed so that they bothcover the same side of the motor vehicle. For this reason, it would beadvantageous to add a third detector and optionally a fourth, whichwould cover the other side of the motor vehicle. Preferably, the thirddetector is, once again, a detector with a wide detection angle andpreferably installed on the second outside rear-view mirror on the motorvehicle. The fourth detector is preferably a detector with a largeradius of action which, preferably is installed at the rear of the motorvehicle. Thus, said third and fourth detectors function in the same wayas the first and second detectors, with the only difference being thatthey are installed on the opposite side of the vehicle.

The detectors with wide angles of detection usually have a radius ofaction between twenty and thirty metres, whereas detectors with greaterradii of action normally include a telephoto lens and their radii ofaction is normally between approximately forty and fifty metres.

As has already been said, the combination of a first detector and atleast one second detector cover the same side of the motor vehicle. I nthis construction, it is advantageous for said combination of at leasttwo detectors provides a single warning signal to the driver, in thesense that the first and second detectors provide combined informationthat indicates the danger status on said side of the motor vehicle. Thisis achieved by arranging for the first and second detectors to share thesame warning devices. Preferably, the warning devices receive a firstcombined signal that is the result of applying the “OR” logic functionto the outputs signals corresponding to the first and second detectors.Thus, if neither of the two output signals corresponds to a determinedalarm level, then the first combined signal will not be able to activatethe corresponding warning device, but if either or both of the twooutput signals correspond to a determined alarm level, the firstcombined signal will activate the corresponding warning device. All thisis also applicable to the third and fourth detectors, in other words,the second pair of detectors that covers the other side of the vehicle,so that the corresponding warning devices that make up a second group ofwarning devices, receive a second combined signal obtained in a similarfashion.

In a situation where the second detector also carries out the functionsof the fourth detector, as previously described, the second detectorwill share the first warning devices with the first detector, and itwill also share the second warning devices with the third detector.Preferably, the second detector is capable of discerning whether thedanger status corresponds to one ort other sides of the vehicle, so thatthe corresponding signal is sent to the first or second warning devices,as applicable.

Preferably, the first, second, third and/or fourth detectors are opticalcameras that are suitable for operation within the visible light and/orinfrared spectrum, such as, for example, those described in the citeddocument WO 01/61371 A2. However, any other type of detector would alsobe possible, in particular a magnetic detector as detailed in aconstruction example described later.

Preferably, each of the detectors is connected to its corresponding dataprocessing device, forming part of a single integrated circuit or via asupport or connection printed circuit (for example, a flexible circuit).

In fact, in this way, communications between the detector and the dataprocessing device may be established directly, without any requirementsfor wiring, which will improve the data transfer speed and facilitatecompliance with electromagnetic compliance requirements (EMC). This willadditionally involve cost benefits.

The second detector and, where applicable, the fourth detector, willpreferably have a large radius of action. This is particularlyadvantageous for the detection of approaching vehicles at longdistances. In the case of highway driving, at high speeds, thislong-range detection will enable the alarm signal to be generated withsufficient time for suitable driver reaction. However, under otherdriving conditions, for example, town driving, the large radius ofaction could produce false or unnecessary alarm signals. For thisreason, it would be advantageous that, under slow speed drivingconditions that are typical of town driving, the large radius-of-actiondetectors are not operational. One preferential method of constructingthe invention would therefore consist of the second detector and, whereapplicable, the fourth detector only being operational above a minimumspeed of the vehicle on which they are installed. This minimum speed maybe defined according to various criteria, which could be, for example,50 kilometres per hour, which is the built-up area speed limit. Anotherpossible value would be, for example, 70 kilometres per hour.Alternatively, instead of the second and/or the fourth detectors beingoperational or not in function of speed, it is possible to simply ignorethe output signals they generate. In this way, it is not necessary forthe detectors to be able to receive an “external” signal (coming fromthe vehicle), something that would both simplify and reduce the costs ofconstruction.

Another preferential form of construction is obtained by fitting some ofsaid detectors with a module that detects vehicles without any relativespeed. One example of a module for the detection of vehicles without anyrelative speed is described in the cited document WO 01/61371 A2. Saidmodule, once it has identified an approaching vehicle, would estimateand monitor its speed and, if it detects that the approaching vehiclespeed is the same as that of the vehicle carrying the active monitoringdevice (with a preset ± tolerance margin) will emit a specific signaluntil there is a change in the detected situation. This module for thedetection of vehicles without any relative speed may be installed inboth the first and third detectors or only in the first, for example, inthe case where the vehicle is not fitted with a third detector.

FIG. 1 shows a saloon car in which certain differentiated areas areindicated within a safety perimeter:

-   -   side areas 41 a and 41 b, which cover a zone visible to the        driver either directly or via auxiliary mirrors and a part of        the blind angle;    -   a frontal area 42, in front of the vehicle, including a blind        angle zone; and    -   a rear area 43, behind the vehicle, including a blind angle        zone.

The cited side areas 41 a and 41 b are covered by means of a group of atleast two detectors 5, 11; 7, 13, which cover areas 5 a, 11 a, and 7 a,13 a, which overlap and complement each other in order to cover a blindside angle.

The front area 42 is covered by a group of two detectors 20, 21 thatcover areas 20 a, 21 a respectively, with partial overlap.

The rear area 43 is covered by part of the cited areas 11 a and 13 a.

The objective of the invention is, through the use of groups of at leasttwo detectors in cooperation to cover a joint detection area or zone, tomake said safety perimeter 40 as large as possible, by suitablycombining the detection angle and radius of action of the employeddetectors and their positions.

FIG. 2 shows a saloon car in which the following areas have beenindicated:

first areas 1, marked with double hatching, which correspond to theareas visible using the outside rear-view mirrors. On the driver's side,this first area 1 has a width of 2.5 metres at a distance of ten metresfrom the rear-view mirror. On the passenger's side, the first area 1 hasa width of four metres at a distance of twenty metres from the rear-viewmirror.

second areas 3, marked by single hatching, which correspond to the areasdetected by a first detector 5, installed on the driver's side rear-viewmirror, and by a third detector 7, installed on the passenger's siderear-view mirror. Both second areas 3 have a width of 4.5 metres atapproximately ten metres distance from corresponding detector 5, 7, inother words from the corresponding rear-view mirror. The length of thesesecond areas 3 is approximately 30 metres.

third areas 9, marked by wider-spaced single hatching, which correspondto the areas detected by a second detector 11, installed, in thisexample, at the far rear left of the saloon car and by a fourth detector13, installed here at the far rear right of the saloon car. These thirdareas 9 have a narrower detection angle than the second areas 3, butthey are some fifty metres long.

Second areas 3 and third areas 9 partially overlap, so that the activemonitoring device has full view, without a continuity solution, up tosome fifty metres away.

FIG. 3 shows a bus in which the following areas have been represented ina similar fashion to FIG. 1:

first areas 1, marked with double hatching, which correspond to theareas visible using the outside rear-view mirrors. On the driver's side,this first area 1 has a width of 2.5 metres at a distance of ten metresfrom the rear-view mirror. On the passenger's side, the first area 1 hasa width of 3.5 metres at 30 metres distance from the rear-view mirrorand a width of 0.75 metres at 4 metres distance from the rear-viewmirror.

second areas 3, marked by single hatching, which correspond to the areasdetected by a first detector 5, installed on the driver's side rear-viewmirror, and by a third detector 7, installed on the passenger's siderear-view mirror. Both second areas 3 have a width of 4.5 metres atapproximately ten metres distance from corresponding detector 5, 7, inother words from the corresponding rear-view mirror. The length of thesesecond areas 3 is approximately 30 metres.

third areas 9, marked by wider-spaced single hatching, which correspondto the areas detected by a second detector 11, installed at the far rearleft of the bus and by a fourth detector 13, installed here at the farrear right of the bus. These third areas 9 also partially overlap withthe second area 3 and, once again, extend beyond the limits of thesecond areas 3, so that the active monitoring device as a whole has atotal radius of action of some sixty metres.

FIG. 4 is an example of the logic connections for the output signalscoming from the group of detectors that cover the same side lane (inother words, the first detector 5 and the second detector 11 or thethird detector 7 and the fourth detector 13). Each detector (in fact,the associated data processing device) generates output signals (thatmay be one or more). For example, FIG. 3 assumes that four outputsignals A, B, C, D, are generated, three for activating three differentcoloured indicator lamps (red, yellow and green) and one for activatingthe acoustic warning. Each front detector output signal (the firstdetector 5 or the third detector 7) is connected to one input of a logic“OR” gate and each corresponding rear detector output signal (the seconddetector 11 or the fourth detector 13) is connected to the other inputof the corresponding logic “OR” gate. In this way, each warning device(red, yellow or green indicator lamps or the acoustic warning) will beactivated whether only one of the two detectors on the correspondingside generates a warning output signal or both simultaneously.

FIG. 5 shows another preferential form of utilising the invention. Inthis case, the second detector 11 and the fourth detector 13 presentdetection areas 9 that at least partially overlap. In this way, theactive monitoring device can employ stereographic vision techniques todetermine the distance and relative speed of objects detected in saiddetection areas 9. This requires that a calculation device receives theimages captured (either just as acquired or suitably processed, forexample, to minimise the flow of information that has to be transmitted)by both detectors 7, 13. This calculation device may be independent fromthe data processing devices for each of the detectors 7, 13. However, itis possible for one of the data processing devices (which are usuallymicroprocessors) to also perform the functions of calculation device. Itis also possible for both detectors to be connected to a single devicethat carries out the functions of the two data processing devices aswell as those of the calculation device.

FIG. 6 illustrates one preferential way of use on a bus or lorry, wheretwo cameras 20, 21 are focussed towards the front of the vehicle, with afirst camera covering a zone 30 that includes a front blind angle and asecond camera 21 positioned on the opposite front section, partlycovering said blind angle zone 30 and extending towards an opposite sidezone 31 of the vehicle. Both cameras 20, 21 will be able to detectmoving objects. Therefore, in the case of, for example, a moving child,animal or object being in front of the vehicle and is not visible to thedriver, the device will detect it and sound the alarm. This alarm signalmay be connected to the vehicle's ignition system so that it cannot bestarted until the driver has verified the situation. FIG. 6 alsorepresents a detector 7 (like the cited third detector) associated withone of the vehicles side mirrors to cover an area 3, and the visiblearea 1 has been indicated on said side.

The front cameras 20, 21 present a detection area that at leastpartially overlaps, and in this zone, when the vehicle is parked,stereoscopic techniques may be employed to determine the height of anobject. The device will determine the height of the object so that ifthis exceeds a certain limit, an alarm signal is generated, which cansubsequently be used to prevent the vehicle from. There will be adeactivation protocol for this alarm signal so that once the situationhas been checked by the driver it will be possible to start the vehicle.

Similarly, in function of whether the vehicle is parked or moving, thecameras can have a different function. Thus, in the case of the frontcameras, when the vehicle is parked (and, for example, by inserting andturning the ignition key to a specific position), said cameras willperform the function of detecting moving objects or obstacles with aheight exceeding a determined value, whereas, when the vehicle is movingat a higher speed, the cameras have a different function, such as thatof following the lines along the roadway as described in referredapplication WO 01/61371 A2.

The bus shown in FIG. 6 will also preferably include a group of at leasttwo cameras, such as those described in FIG. 3, on one or both sides.

The cameras may also have a different use in function of the vehicle'sspeed by entering the speed into a control system for said cameras, eachone switching to a different program routine in function of thevehicle's speed value and the camera position.

Another possibility of applying the invention's principles consists ofusing a group of two or more cameras at the rear of the vehicle, with afirst camera focussed towards the rear blind angle and a second camerato a zone of this blind angle that extends to one of the sides.Detection of movement and also of obstacles will be carried out in thisrear zone, together with the distances to them. These rear cameras willbe operational with respect to these functions only when the vehicle isparked and will generate an alarm when reverse gear is engaged or whenthe vehicle begins to move backwards. This will also require the inputof the vehicle's speed and reverse gear signals into the control systemfor said cameras. Within a range of forward speeds, for example, betweenfive and sixty kilometres per hour, these rear cameras will benon-operational. In the case of the vehicle moving at a positive speed(forwards) and above a certain threshold (for example, sixty kilometresper hour), the cited rear cameras will have the function of being asecond detector for vehicles at long distances, operating in combinationwith the front cameras (cited first and third detectors 5, 7). Thus, inthis case, the rear cameras will have a different function depending onthe vehicle's speed and the position of said cameras.

The invention also contemplates the use of magnetic sensors asdetectors, such as those described in Spanish patent application200101105 from the same applicant, for detecting (approximately sixmetres range) the presence of objects in a blind angle of the vehicle,where said objects contain at least one ferromagnetic material in such away that it would cause distortion of the earth's magnetic field,together with the installation of a logic circuit with neural networksfor processing the signals coming from the sensors, in other words, aprocessor or neural network that can be identical to the one employedfor processing the signals from the cameras.

In particular and in accordance with the invention, it is intended that,for example, said second and fourth detectors 11, 13 described in theexamples of FIGS. 2 and 3 consist of the means to detect a distortion inthe earth's magnetic field, and being suitable to detect at least two ofthe three spatial components of the magnetic field.

In a preferred construction, said second and fourth detectors 11, 13comprise a magnetic field sensor, prepared to detect at least two of thethree spatial components in a magnetic field and able to generateelectrical signals in function of the detected magnetic field, and saidsensors are installed symmetrically with respect to the vehicle'slongitudinal axis, and are connected to an electronic circuit thatcalculates the difference of the signals generated by each of saidsensors. The preferred configurations would be a combination of cameraand magnetic sensor at the front of the vehicle (one on each side of thevehicle), together with cameras on the outside rear-view mirrors andmagnetic sensors at the rear of the vehicle, one on each side in orderto obtain better coverage.

In addition to low cost, the use of magnetic sensors has the advantageof being able to detect vehicles under low-light conditions (dazzlingand fog etc), in other words, it takes advantage of the insensitivity ofsuch detectors to weather conditions.

The method proposed by the invention for active monitoring within asafety perimeter for a motor vehicle for the purpose of detecting movingobjects and static obstacles in an area of risk, close to said vehicle,consists of the following basic stages:

-   -   the acquisition of information from at least two differentiated        detection zones within said safety perimeter, by means of a        group comprising a first detector 5, 20 that covers a first zone        and at least one second detector 11, 21 that covers a second        zone, either contiguous or partly superposed on said first zone        and extending it, with both detectors cooperating to define a        combined detection zone that includes a sector of said safety        perimeter,    -   processing of the signals acquired by at least two detectors 5,        20, 11, 21, and    -   the generation of warning signals in the case of detecting an        object that could involve a risk or due to the presence of an        insurmountable obstacle existing in one of the joint detection        zones, applying a “OR” logic function to said processed signals,        corresponding to said first detector 5, 20 and to said second        detector 11, 21.

According to a preferred method of construction, the processing of thedetector signals consists of a separate, simultaneous treatment of theinput signals provided by said first 5, 20 and second detectors 11, 21.

Additionally, in function of the position occupied by each of saidgroups of detectors 5, 20; 11, 21 on the vehicle, a differentiatedprocessing is intended for the data captured by each detector.

In a similar fashion, in function of the vehicle's speed, each of thecited detectors 5, 20; 11, 21 can be activated or not, be ignored orperform a differential processing of the captured data.

In order to implement the method in the most efficient way, it isintended to use several groups of detectors, each consisting of a firstand at least one second detector applied to cover several sectors ofsaid safety perimeter, with the detectors of each group sharing the samewarning means, specific to each group.

The various components of the active monitoring device can beinterconnected in various manners. It is possible to communicate thedetectors with a central processor via a specific communicationsnetwork. The central processor can receive the images just as they arecaptured, pre-processed and/or compressed or the output signals oftreatment by the previously described data processing devices. Thecentral processor may be located anywhere and any communicationsprotocols may also be employed. In particular, these can be of theFirewire, BlueTooth, MOST, USB2 types or others which, because of theirtransmission speeds and bandwidth permit the transmission of a largeamount of data at speeds that allow real-time data processing. In thiscase, the central processor is responsible for decoding the compresseddata coming from each detector and/or processing the information thathas to be presented to the driver. The central processor and/or each ofthe detectors can receive extra data over the vehicles communicationsnetwork (or networks), which will enhance the response of the activemonitoring device, with respect to the various driving conditions,reducing the number of false alarms. Possible parameters that could bereceived over the vehicle's communications network are the vehiclespeed, data from the vehicle steering and inclination sensors andsignals from the left and right indicators etc.

By having data from the vehicle steering and inclination sensors andabout its speed, it becomes possible for the detectors to adapt theirfunctions, in particular, the detection zone depending on theseparameters.

It is also possible for the interconnection between at least some of thecited groups of at least two detectors 5, 11; 20, 21; 7; 13 that themeans of processing their input signals and the cited warning means iscarried out by radiofrequency communications.

Alternatively, one of the data processing devices can carry out thefunctions of central processor, together with its own functions, inwhich case, the data processing device will be additionally connected tothe vehicle communications network (or networks). Or, the centralprocessor could perform the functions of all the data processing devicestogether with its own functions.

It is also possible that the communications between detectors do notoccur over a specific network, but instead, it makes use of thevehicle's communications network (or one of its networks).

Finally, it is possible that there are no communications between thedetectors, instead they limit themselves to transmitting their outputsignals (via their corresponding data processing devices), withoutreceiving any data from the rest of the vehicle or the other detectors.Only the central processor received data from the vehicle andsubsequently transmits data to the vehicle.

1.-37. (canceled)
 38. An active monitoring device within a safetyperimeter of a motor vehicle, for the detection of moving objects orstatic obstacles within said safety perimeter, comprising: a firstdetector which has a first detection angle and a first radius of action,which covers a first detection zone that includes at least part of ablind angle of said vehicle, where said first detector transmits inputsignals to at least one data processing device that generates outputsignals suitable to activate warning means for the driver; at least asecond detector, which has a second detection angle and a second radiusof action, which covers a second detection zone and forms, with saidfirst detector, a group, with said first and at least one seconddetectors cooperate in order to cover a combined detection zone of saidblind angle, which is enlarged with respect to that covered by the firstdetector and which forms a sector of said safety perimeter; said firstand at least one second detectors of said group share the same warningmeans that can be activated via the processing of the output signalsfrom each one; and at least one of said detectors is an optical cameracapable of operation the visible and/or infrared spectra.
 39. A devicein accordance with claim 38, wherein each of the cited detectors can beactivated or not or perform differential processing on the capturedinformation as a function of the vehicle's speed.
 40. A device inaccordance with claim 38, wherein said first detector is orientedtowards a side lane adjacent to said motor vehicle and said at least onesecond detector of said group, is oriented, at least partly, towardssaid same side lane and the area covered by said second detector extendstowards the rear of the vehicle.
 41. A device in accordance with claim40, wherein said at least one data processing device operates byprocessing simultaneously and separately, each of said input signals.42. A device in accordance with claim 38, wherein said first detector,of said group, covers a blind angle that extends in front of the vehicleand extends towards a first side zone and said at least one seconddetector covers an area that extends to the front of the vehicle towardsa second zone located on the opposite side of the vehicle.
 43. A devicein accordance with claim 38, wherein said first detector of said groupcovers a blind angle that extends in front of the vehicle and extendstowards a first side zone and said second detector covers a zone thatextends to the rear making longer a second side zone opposite said firstside zone.
 44. A device in accordance with claim 40, wherein in additionto a first group having said first and at least one second detector,oriented towards a side lane adjacent to the vehicle, it comprises asecond group having first and second detectors, where said firstdetector covers a blind angle that extends in front of the vehicle andextends towards a first side zone and said second detector covers anarea that extends in front of the vehicle towards a second zone locatedon the opposite side of the vehicle.
 45. A device in accordance withclaim 40, wherein in addition to a first group having said first and atleast one second detector on one side of the vehicle comprises a secondgroup having first and second detectors, where a first detector of thesecond group covers a blind angle that extends in front of the vehicleand extends towards a first side zone and a second detector of saidsecond group coincides with the first detector of the first group.
 46. Adevice in accordance with claim 38, wherein said first detection angleis wider than said second angle and in that said second radius of actionis larger than said first radius of action.
 47. A device in accordancewith claim 38, wherein the position of said second detector in thevehicle is such that it can detect a vehicle in said side lane at adistance from said motor vehicle that is greater than the radius ofaction of said first detector and in that it is intended to employdifferential processing of the data captured by said first and seconddetectors as a function of their positions on the vehicle.
 48. A devicein accordance with claim 40, further comprising a third detectororiented towards a lane adjacent to said motor vehicle, which covers adetection zone that includes at least part of a blind angle of saidvehicle, with said third detector being placed on a side of the vehicleopposite that of said first detector.
 49. A device in accordance withclaim 48, further comprising a fourth detector installed at the rear ofsaid motor vehicle, or on a side zone, more rear than the cited thirddetector, on a side of the vehicle opposite that covered by said firstdetector and in that said third and fourth detectors cooperate to covera first zone of an adjacent lane and a second zone that extends to therear of the vehicle, operating as one of said groups having first andsecond detectors.
 50. A device in accordance with claim 42, comprisingtwo groups of a first and second detectors on opposite sides of thevehicle.
 51. A device in accordance with claim 38, wherein said firstdetector is installed in the body or structure of an outside rear-viewmirror on said motor vehicle.
 52. A device in accordance with claim 51,wherein said second detector is installed at the rear of said motorvehicle or in a side zone, more rear than the cited first detector. 53.A device in accordance with claim 41, wherein said group having a firstand at least one second detector is installed in the body or structureof an outside rear-view mirror on said motor vehicle.
 54. A device inaccordance with claim 38, wherein said warning means receives a firstcombined signal, where said first combined signal is obtained byapplying a “OR” logic function between said processed output signalscorresponding to the first and second detector, of each group having onefirst and at least one second detector.
 55. A device in accordance withclaim 49, wherein said third and fourth detectors share the same warningmeans.
 56. A device in accordance with claim 55, wherein said warningmeans receives a second combined signal, where said second combinedsignal is obtained by applying a “OR” logic function between saidprocessed output.
 57. A device in accordance with claim 38, wherein eachof said detectors of said groups having at least two detectors thatcooperate to cover a combined detection zone are directly connected to acorresponding data processing device, forming part of a singleintegrated circuit or connected to said processor via a support orconnection printed circuit.
 58. A device in accordance with claim 49,wherein said second and fourth detectors comprise detection means fordetecting the distortion of the earth's magnetic field and suitable forthe detection of at least two of the three spatial components of amagnetic field.
 59. A device in accordance with claim 49, wherein saidsecond and fourth detectors are made up of a magnetic field sensorcapable of generating electrical signals as a function of said magneticfield, and prepared to detect at least two of the three spatialcomponents of a magnetic field and in that said sensors are installedsymmetrically with respect to the vehicle's longitudinal axis, and areconnected to an electronic circuit that calculates the difference of thesignals.
 60. A device in accordance with claim 49, wherein said seconddetector and/or said fourth detector are located at the rear of thevehicle or on a trailer of the same and which are only activated at aminimum speed of said motor vehicle.
 61. A device in accordance withclaim 49, wherein said group having a first and at least one seconddetector include a module for the detection of vehicles without anyrelative speed, in other words travelling at the same speed as thevehicle fitted with said detectors, within a preset margin of tolerance.62. A device in accordance with claim 49, wherein only said firstdetector of each group is fitted with a module for the detection ofvehicles without any relative speed.
 63. A device in accordance withclaim 49, wherein said second and fourth detectors are comprised of anoptical camera and present detection areas that overlap at leastpartially and in that said device employs stereoscopic vision techniquesto determine the approximate distance and relative speed of objectsdetected within said detection areas, when the vehicle in motion, or theheight and/or movement of objects or the distances to them, when thevehicle is parked.
 64. A device in accordance with claim 42, whereinsaid first and second detectors are comprised of an optical camera andpresent detection areas that overlap at least partially and in that saiddevice employs stereoscopic vision techniques to determine the heightand/or movement of objects located within said detection areas when thevehicle is parked.
 65. A device in accordance with claim 49, wherein theinterconnection between at least part of the cited detectors he means ofprocessing their input signals and the cited warning means is performedby radiofrequency communications.
 66. A device in accordance with claim38 further comprising means to display an image of at least part of thefield covered by the cited cameras.
 67. A device in accordance withclaim 49, wherein all the detector devices comprise optical camerasworking in the visible light and/or infrared spectra.
 68. An activemonitoring method within a safety perimeter of a motor vehicle for thedetection of moving objects or static obstacles in an area of risk closeto said comprising the steps of: acquiring data from at least twodifferentiated detection zones within said safety perimeter by means ofa group comprising a first detector that covers a first zone and atleast one second detector that covers a second zone which is contiguousor partly superposed to said first zone and which extends it, defining ajoint detection zone, which includes a sector of said safety perimeter,with at least one of said detectors being an optical camera suitable forworking in the visible light and/or infrared spectra; processing thesignals acquired by at least two detectors; and generating warningsignals in the case of detecting an object involving risk or aninsurmountable obstacle, existing in said joint detection zone, applyinga “OR” logic function to said processed signals, corresponding to saidfirst detector and to said second detector.
 69. A method in accordancewith claim 68, wherein said process comprises a simultaneous, separatetreatment of the input signals provided by said first detector andsecond detector.
 70. A method in accordance with claim 68, wherein adifferentiated processing of the data captured by each detector iscarried out as a function of the position occupied by each of saidgroups of detectors on the vehicle.
 71. A method in accordance withclaim 68, wherein each of the cited detectors is capable of beingactivated or not, of being ignored, or of carrying out differentialprocessing of the captured data as a function of the vehicle speed. 72.A method in accordance with claim 68, wherein it comprises using severaldetector groups, each comprising of a first and at least one seconddetector employed to cover several sectors of said safety perimeter,with the detectors sharing the same warning means, specific for saidgroup.